title: A 13µW 87dB dynamic range implantable ΔΣ modulator for full-spectrum neural recording.
abstract: Experiment analysis on in-vivo data sequences suggests a wide system dynamic range (DR) is required to simultaneously record local field potentials (LFPs), extra-cellular spikes, and artifacts/interferences. In this paper, we present a 13 µW 87 dB DR ΔΣ modulator for full-spectrum neural recording. To achieve a wide DR and low power consumption, a fully-differential topology is used with multi-bit (MB) quantization scheme and switched-opamp (SO) technique. By adopting a novel fully-clocked scheme, a power-efficient current-mirror SO is developed with 50% power saving, which doubles the figure-of-merit (FOM) over its counterpart. A new static power-less multi-bit quantizer with 96% power and 69% area reduction is also introduced. Besides, instead of metal-insulator-metal (MIM) capacitor, three high-density MOS capacitor (MOSCAP) structures are employed to reduce circuit area. Measurement results show a peak signal-to-noise and distortion ratio (SNDR) of 85 dB with 10 kHz bandwidth at 1.0 V supply, corresponding to an FOM of 45 fJ/conv.-step. which is implemented in a 0.18 µm CMOS.
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Md Kafiul
authors.initials: MK
authors.lastname: Islam
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000669:Amplifiers, Electronic; D000703:Analog-Digital Conversion; D000818:Animals; D003198:Computer Simulation; D025802:Electric Capacitance; D004567:Electrodes, Implanted; D004827:Epilepsy / Q000503:physiopathology; D006801:Humans; D058117:Neural Prostheses; D009474:Neurons / Q000502:physiology*; D051381:Rats; D013997:Time Factors; D059015:Wireless Technology